Micro-electro-mechanical system (MEMS) technology is the integration of very small mechanical devices installed inside a silicon substrate such as sensors, valves, gears, reflecting mirrors, and drivers on a computer. Thus, MEMS devices are often called intelligent machines. To protect against external interference during operation, it may be desirable to bond with a cap substrate to hermetically seal the MEMS devices to form a semiconductor apparatus. Furthermore, in many applications, it is also desirable for the bonded substrates to include integrated circuit (IC) devices.
However, there are challenges to implementing such features and processes in MEMS or IC device fabrication. For example, in a “substrate bonding” process, it is difficult to achieve a low-contact-resistance bond between bonded substrates because high-contact-resistance materials are generated in the interface between the bonded substrates, thereby increasing the likelihood of semiconductor apparatus instability and/or semiconductor apparatus failure.
Accordingly, what is needed is a method to form a low-contact-resistance bond between bonded substrates.